Adjustable oil burner

Dec. 23, 1941. κ. κ. η. eweryd etal 2,267,451

ADJUSTABLE OIL BURNER Filed Oct. 5, 1939 2 Shee.ts-Sheet 1

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Dec. 23, 1941. κ. κ. h. eweryd etal 2,267,451

ADJUSTABLE OIL BURNER

Sheets-Sheet 2

Filed Oct. 5, 1939

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Patented'Dec. 23,1941

2,267,451

UNITED STATES PATENT OFFICE

2,267,451 ADJUSTABLE OIL BURNER

Knut Karl Herman Eweryd and Tor Axel tidman, Karlskrona, and Lars Axel Widing, Stockholm, Sweden, assignors to Aktiebolaget Gotaverken, Gothenburg, Sweden, a corporation of Sweden

Application October 5,1939, Serial No. 298,062 In Sweden October 6,1938

Claims. (Cl. 158—73)

This invention relates to improvements in adjustable oil burners for boilers, hot water heaters or other heating plants.

The conventional oil burners, which are at present available, cannot be manufactured for 5 lower oil capacity than about 2 kilogrammes of oil per hour. This is due to the practical impossibility of producing oil burner nozzles with orifices for smaller oil delivery than 2 kilogrammes per hour at the lowest practical oil pressure, 10 which will maintain atomization of the oil. Considering, for instance, an oil with a heating value of 10,000 kilogramme calories per kilogramme of oil, the quantity of heat which is liberated by the combustion of the oil delivered by an oil burner 15 of the above mentioned conventional type, is at least 20,000 kilogramme calories per hour, and consequently, the necessary heat exchange surface in an ordinary water heating apparatus is at least two square meters, if economical heat 20 exchange is to be obtained.

When such an oil burner is provided in a small heating plant, the heat exchange surface is usually insufficient and the combustion chamber too small for said oil quantity. This results in heat 25 losses and a considerable amount of unburned products in the combustion gases. Since the maximum heat consumption per hour in a small heating plant is often much less than the smallest heat quantity supplied by the conventional oil 30 burners, it has hitherto been necessary to operate such burners intermittently, which causes disturbances and necessitates a complicated control apparatus.

One object of the present invention is to pro- 35 vide means for varying the oil quantity supplied by an oil burner to a combustion zone within wider limits than has hitherto been possible.

For this purpose we provide an oil burner according to the invention with a spraying nozzle &lt;0 with variable spraying angle and adjacent to the path of the oil jet delivered by said nozzle there is located means for catching a portion of said oil jet, so arranged that the oil, which passes the catching means, is fed to the combustion zone of ⁴⁵the burner whereas the oil which is caught by the catching means is conducted away without entering the combustion zone.

With an oil burner of this type it is possible to control the oil quantity supplied to the combus- ⁵⁰tion zone according to the momentary variations of the heat consumption of the heating apparatus automatically or manually within very wide limits. For instance, a burner nozzle, which at normal oil pressure delivers five kilogrammes of 55.

oil per hour, may easily be adjusted so that the peripheral parts of the oil jet are retained by the catching means and the oil quantity supplied to the combustion zone is reduced to 10 per cent of the total capacity of the nozzle, that is to 0.5 kilogramme of oil per hour. In such a case the combustion zone is supplied with 5,000 kilogramme calories per hour and it is then possible, for instance, to operate a heating apparatus with less than one square meter heat exchange surface continuously without undue losses in the combustion gases.

A further object of the invention is to combine the adjustable spraying nozzle with an adjustable oil catching means in order to increase still further the range within which the oil burner may be operated. Further features of the invention are set forth in the following specification and claims.

In the accompanying drawings some embodiments of the invention are illustrated by way of example.

Fig. 1 is a vertical section of a heating plant provided with an oil burner according to the invention.

Fig. 2 is a longitudinal section of an oil burner according to one embodiment of the invention on a larger scale.

Fig. 3 is a section on line III—III in Fig. 2.

Figs. 4 and 5 are longitudinal sections of two further embodiments of oil burners according to the invention.

Fig. 6 is a longitudinal section of an adjustable spraying nozzle for an oil burner according to the invention.

Fig. 7 is a detail of a control device for said nozzle.

Fig. 8 is a section on line VIII—VIII in Fig. 6.

Fig. 9 is a longitudinal section of an adjustable spraying nozzle according to a further embodiment of the invention; and

Fig. 10 is a cross-sectional view taken on the line X—X of Fig. 5. ¹

Fig. 1 shows a plant comprising a heating apparatus I provided with an oil burner according to the invention. The heating apparatus, which ^may naturally be of any design, comprises a combustion chamber 2, heat exchange portions 3 and a combustion gas outlet 4. Thermostatic control devices 5 and 6 are provided with their heat sensitive members 7 and 8, respectively, extending into the combustion gas outlet 4 and the hot water jacket of the heating apparatus • A fuel oil tank 9 is connected by means of a conduit 10 to an oil pump II of conventional

2,267,461 design driven by an electric motor 12, which also drives a fan or blower 13 for the combustion air. The device 5 may be a switch adapted to interrupt the circuit of the motor when the gas temperature in the outlet 4 falls below a certain 5 value. The oil pump, the motor and the fan are mounted on a tubular shaft 14 journalled in a casing 15 carried by a support 16. If a sufficient natural draught is available the fan may be omitted. The oil burner comprises a burner io housing 17, which forms the front end of the casing 15 and Is secured in an opening 18 in the heating apparatus I. The burner housing 17 contains an adjustable spraying nozzle 19, which, through a tubular stem 29 extending through 15 the shaft 14, is connected with a device 21 for controlling the spraying angle of the nozzle, which device is described in detail in connection with Figs. 6 and 7. The control device 21 is actuated by the thermostat 6 through a flexible cable 22 20 such as a Bowden cable, and increases the spraying angle of the nozzle when the water temperature rises and vice versa. A spray oil catching means 23 in the shape of a drum surrounds the nozzle 19, and more or less of the oil delivered 25 by the nozzle is caught by said means as the spraying angle is increased or reduced. A housing 24 serves to gather superfluous oil. A conduit 25 leads oil from the oil pump 11 to the control device 21, which is connected with the nozzle, 30 and another conduit 26 is provided for leading superfluous oil from the housing 24 back to the oil tank 9.

The oil burners illustrated in Figs. 2, 4 and 5 may replace the burner indicated in Fig, 1, and 35 may in similar manner be built together with casings containing an oil pump, a fan and a motor, but they may also be incorporated in any other known type of oil burner assembly.

The burner according to Figs. 2 and 3 com- 4() prises a burner housing 27, which may be secured to a wall of a combustion chamber of a heating apparatus by means of a flange 28 in the same manner as illustrated in Fig. 1. The housing 27 serves to lead combustion air to the 45 combustion chamber. A nozzle 29 with an adjustable spraying angle is provided within the drum-shaped nozzle housing 30 in the burner housing 27. 31 is a stem, which cdifeins fuel supply conduits and connects th'e nozzle with a 50 spraying angle control device as will be hereinafter described in connection with Figs. 6 and 7. The nozzle housing 30 is provided with openings 32 serving to prevent pressure reductions within the nozzle housing during the operation of the 55 nozzle and to admit air to the jet immediately in front of the nozzle in the nozzle housing. A drum-shaped oil catching or gathering means 33 Is secured in front of the orifice of the nozzle 29 and forms a collecting surface for oil deposited 60 on said surface according to the momentary adjustment of the spraying angle of the oil jet 34. The catching drum 33 tapers towards the nozzle 29, as illustrated in Fig. 2, but said drum may . naturally be of cylindrical or other suitable shape. 65 At the large open end of the drum 33 a peripheral collecting groove 35 is formed for collecting oil deposited on the inner surface of the drum 33 and conveyed to said groove by the pressure produced by the jet. The oil collected in the 70 groove 35 is drained off through a conduit 36 and returned to the oil supply tank 9, as illustrated in Fig. 1. The large end of the drum 33 is connected with a deflector plate 37, which directs a portion of the air towards the oil jet ⁷⁵ and which is connected with the burner housing 27 and the drum 33 by means of plates 38 and 39, respectively, Fig. 3, which, if desired, may be adapted to produce a whirling motion of the air flowing to the combustion chamber through the burner housing 27 around the nozzle housing 30. When the spraying angle of the nozzle 29 is adjusted to a value near the taper angle of the drum 33, all oil delivered by the nozzle flows into the combustion chamber through the open end of the burner housing 27. However, ’ as the spraying angle of the nozzle is increased, more and more of the peripheral portions of the oil jet 34 is deposited on the inner surface of the drum 33 and moved towards the groove 35 and conducted back to the oil tank and thus withdrawn from the combustion process in the heating apparatus. If the pressure of the oil supplied to the nozzle 29 is substantially constant, the amount of oil delivered by the nozzle will be substantially constant independently of the momentary spraying angle, and, consequently, the amount of oil supplied to the combustion chamber varies substantially in inverse ratio to the size of the spraying angle.

In the embodiment according to Fig. 4 a burner housing 40 is provided with a flange 41 for securing the burner to a heating apparatus such as I in Fig. 1. Oil under pressure is admitted through a hollow stem 42 to a nozzle 43, the spraying angle of which may be adjusted automatically or manually by means of a rod 44 extending through the stem 42, as will be described in detail in connection with Fig. 9. The angle of the oil jet 45 delivered by said nozzle may be varied over a wide range but the amount of fuel delivered by the nozzle at a certain oil pressure is substantially constant irrespective of the prevailing spraying angle. The spraying nozzle 43 is disposed in a nozzle housing 46, which is provided with air inlet openings 47, through which air is admitted to the interior of the nozzle housing 46. The housing 46 is provided with a front wall 48 forming an oil catching means and having an opening 49. The amount of oil supplied to the heating apparatus depends upon the relation between the area of the opening 49 and the total cross-sectional area of the oil jet in the plane of said opening. Consequently, the amount of oil supplied to the heating apparatus depends directly upon the spraying angle of the jet and may be varied from a maximum value, when all oil delivered by the nozzle is injected into the heating apparatus and the spraying angle is so small that all of the oil jet passes through the opening 49, to a very low value corresponding to the largest obtainable jet angle. The oil particles deposited on the inner surface of the wall 48 and the nozzle housing 46 flow to the bottom of the nozzle . housing and escape through an opening 50 to a collecting chamber 51, from which a drain pipe 52 leads the oil back to the oil tank or the pump, respectively. An external wall or shield 53 is provided in front of the wall 48 and has an opening 54 corresponding to the opening 49. A space 55 is formed between the shield 53 and the wall 48, in which space oil deposited on the edges of the opening 49.1s gathered and from which said oil is conducted to the chamber 51. A deflecting plate 56 and guide vanes 57 and 58 are provided in the space between the nozzle housing 46 and the drum-shaped burner housing 40, said plate and vanes serving to direct the air into close contact with the oil jet so as to produce a perfect mixture.

IS

2,267,451

In the embodiment illustrated in Figs. 5 and 10 an adjustable spraying nozzle 59 is provided in a nozzle housing 60 disposed in a burner housing 61 provided with an external flange 62 for securing the burner to a heating apparatus such as the apparatus illustrated in Fig. 1. The nozzle housing 60 is provided with air inlet openings 63 and an oil outjet opening 64 in a lower portion of the housing communicating through a drain pipe 65 with the oil tank. Oil under pressure is admitted to the nozzle through a hollow stem 66, which may be connected to a control device such as 21 in Fig. 1, and a jet 61 with variable spraying angle is delivered by the nozzle. At a suitable distance in front of the nozzle a catching means in the form of an iris diaphragm 68 is provided, which may be operated automatically or manually by means of a rotatable shaft 69 and a gear wheel 70 co-operating with the diaphragm. Only the oil particles which pass through the opening 71 of the diaphragm 68 are injected into the combustion chamber of the heating apparatus, whereas the other particles of the jet are deposited on the diaphragm 68 and flow down into the lower portion of the nozzle housing 60 25 and through the opening 64 and the pipe 65 back to the oil tank. A second diaphragm or cover 72 is provided outside the iris diaphragm 68 and oil which may flow down along the outer surface of the iris diaphragm is gathered in a space 73 30 inside the cover 72 and conducted to the drain pipe 65. A deflecting plate 74 and guide vanes or plates 75 and 76 are provided in the opening of the burner housing 6| in similar manner as described hereinabove in connection with Figs. 2 35 and 4. The opening 77 in the cover 72 is somewhat larger than the maximum opening of the iris diaphragm 68 and co-axial with said opening.

Figs. 6 and 9 illustrate two different embodiments of spraying nozzles with adjustable spray- 40 ing angle, which may be used in connection with the oil burners according to the invention, but other adjustable nozzles of known constructions may also be employed in connection with the invention.

In the spraying nozzle according to Fig. 6, which is employed in the oil burners illustrated in Figs. 1, 2 and 5, fuel oil under pressure is supplied to a distribution chamber 78 in a body 21, Figs. 1 and 6, from which the oil flows through a pipe 79 and a duct 80 to a central chamber 81 in the nozzle body 82. From the chamber 81 the oil flows through a duct 83 to a centrally disposed circular chamber 84 formed by two bodies __________ ________w ,,, _ana and 86, which are held in place by means of 35 thereby the spraying angle of the nozzle The a collar 87 screw-threaded onto the nozzle body. ------’----- ' - ·

The body 85 is provided with an eccentric bore 88 communicating with the chamber 84 through a slot 89, Fig. 8, directed tangentially towards the circular chamber 84. ' * ________;__ through a duct 90 and a pipe 91 with the chamber 78. The supply of pressure oil to the pipes 79 and 91 is controlled by two plungers 92 and 93 operated by means of a cross piece 94, a lever 95 and a rod 96. The cross piece 94 is journalled on _6Sa pivot 97 and the plungers 92, 93 are movable in bores 98 and 99 in the body 21 so that the same oil quantity is always admitted to the nozzle and so that the oil quantity flowing through the duct relatively to the oil quantity flowing through ₇₀ tion fe alwaVs““obt“ataed,’ which Ts not^ways the duct 89 varies according to the position taken t^u--------- - · ««ways by the cross piece 94, which depends upon the water temperature in the heating apparatus.

For this purpose the thermostatic control device _____________„,,_{c np}

6, 8, Figs. 1 and 7, contains a rod 113 with a 75 scribed and illustrated in the drawings should different coefficient of elongation than the tube 8, which actuates the flexible cable 22 and the rod 96 against the action of a spring 114, Fig. 6. The oil is delivered by the nozzle through the orifice 100, and if all the oil delivered by said orifice comes through the central duct 83, that is if the plunger 93 has closed the bore 99, the spraying angle of the jet is a minimum and the burner injects the maximum oil quantity into the heating apparatus. If, on the contrary, all the oil delivered by the nozzle flows to the chamber 84 through the tangential duct 89 only, that is if the plunger 92 has closed the bore 98, the oil in the chamber 84 is caused to rotate rapidly and the maximum spraying angle is obtained, which may be some 160°. A variation of the relation between the oil quantities supplied through the ducts 83 and 89 results in a perfectly continuous variation of the spraying angle of the nozzle. The lever 95 may naturally be operated manually instead of automatically and the illustrated control valve mechanism may be replaced by a three way cock or separately operated valves for the different oil conduits.

In the embodiment illustrated in Fig. 9 and employed in the burner according to Fig. 4 the nozzle body 101 is provided with a fuel supply pipe 102 connected through a duct 103 with an annular chamber 104. A valve 105, which is screw-threaded at 106 in the nozzle body 101, is rotatable by means of a rod 101 corresponding to 44 in Fig. 4 to and from a conical seat formed by a body 108, which is secured at the end of the nozzle body 101 by means of a collar 109 screwthreaded onto the nozzle body. The body 108 is provided with an orifice 110 and a central circular chamber 111 is formed in the valve and between the end of the valve and the conical valve seat formed by the body 108. The valve is provided with a duct 112 leading tangentially from the annular chamber 104 to the chamber III. When the valve 105 is in its foremost position, as illustrated in Fig. 9, all oil delivered by the orifice passes through the duct 112 and, consequently, 45 maximum rotation of the oil in the chamber I 11 and maximum spraying angle is obtained. In every other position of the valve 105, the oil also flows radially to the chamber I f I through the space between the conical valve and the valve CO seat formed by the body 108 so that less rotation is produced in the chamber ΗI. Consequently, the position of the valve directly determines the relation between the oil quantities flowing tanfentiaily and radially to the chamber III and _ _________UUAXkJ spraying nozzle according to Fig. 9 also permits a completely continuous variation of the spraying angle of the oil jet delivered by the nozzle and, consequently, also of the fuel oil quantity injected

The bore 88 is connected ₆₀ into the combustion chamber. The rod 101 may ^a m·™ Oi _be connected to a thermostatic control device at the heating apparatus or it may be adjusted manually by means of a suitable hand wheel or the like provided on the rod.

When the spraying angle of the nozzles above described is varied, the oil density of the jets is also varied but the degree of atomization is substantially the same for different spraying angles, and, consequently, a satisfactory eombus_ winuii is uol always the case when the oil quantity delivered to the combustion zone is controlled by variation of the pressure of the oil supplied to the nozzle.

The embodiments of the invention above' de87,481 ing to the adjustment of said catching means to catch more or less of said oil jet and to prevent caught oil from entering the combustion zone of the burner.

S 5. In an oil burner, a spraying nozzle with variable spraying angle for atomizing fuel oil supplied to said nozzle, an oil catching means disposed adjacent to the path of an oil jet delivered by the nozzle and adapted to catch portions of 10 said oil jet and to prevent caught oil from entering the combustion zone of the burner, and means providing an adjustable opening in said catching means for admitting at will a desired portion of the oil jet into the combustion zone of the burner.

6. In an oil burner, a spraying nozzle with variable spraying angle for atomizing fuel oil supplied to said nozzle, an iris diaphragm disposed in the path of an oil jet delivered by the nozzle and adapted to catch more or less of said oil jet 20 according to the momentary adjustment of said diaphragm and to prevent oil caught by the diaphragm from entering the combustion zone of the burner, and means for varying the opening of the iris diaphragm.

7. In an oil burner, a spraying nozzle with variable spraying angle for atomizing fuel oil supplied to said nozzle, a means for controlling said spraying angle of the nozzle, a temperature sensitive device provided in heat exchange relation with medium heated by the burner and adapted to actuate said controlling means according to , the temperature of said medium, and an oil catching means disposed adjacent to the path of an oil jet delivered by the nozzle and adapted to catch portions of said oil jet and to prevent oil caught by said catching means from entering the combustion zone of the burner.

8. In an oil burner, a spraying nozzle with variable spraying angle for atomizing fuel oil sup⁴⁰ plied to said nozzle, a housing surrounding said nozzle, and a portion of said housing remote from the nozzle forming an oil catching means disposed adjacent the path of an oil jet delivered by the nozzle and adapted to catch portions of said oil ⁴³ jet and to prevent caught oil from entering the combustion zone of the burner.

KNUT KARL HERMAN EWERYD. TOR AXEL 0DMAN.

LARS AXEL WIDING.

2,2 only be considered as examples and the invention may naturally be modified in several different ways within the scope of the following claims.